This invention relates to a method and apparatus for controlling a cylinder grinding machine, more particularly a long and relatively small diameter cylinder.
In order to work a slender cylindrical workpiece at a high accuracy it is necessary to control the grinding machine such that an axis interconnecting a headstock and a tailstock which are used to rotatably support the both ends of the workpiece is parallel with the direction of movement of a grinder or the cylindrical workpiece. A deflection suppressing device provided with rest members engaging the cylindrical workpiece is provided at a position confronting a grinding wheel for the purpose of preventing the flexure of the intermediate portion of the cylindrical workpiece causing the flexure or a small vibration of the grinder.
Heretofore, the adjustments of the parallism of the axes and of the rest members of the deflection suppressing device have been made manually. In recent years, however, owing to the requirement for automating the grinding machine, the automation of the workpiece supporting device has been developed. For example, as disclosed in Japanese Laid Open Patent Specification No. 5761/1987, a grinding machine has been proposed including a workpiece supporting device having a dimension measuring device which measures the diameter of the cylindrical workpiece so as to detect the contact condition of the rest members of the deflection suppressing device against the cylindrical workpiece.
As above described, in a prior art grinding machine equipped with a workpiece supporting device, a dimension measuring device has been provided for detecting the contact condition of the rest members of the deflection suppressing device against a cylindrical workpiece so as to prevent unsatisfactory supporting condition of the workpiece supporting device and to ensure accurate operation of the workpiece supporting device.
The longitudinal axis of the cylindrical workpiece tends to become not parallel with the direction of the movement of the cylindrical workpiece or the axis thereof caused by the deflection of the central portion, particularly of a cylindrical workpiece of a relatively small diameter, thereby decreasing the working accuracy, the deflection being caused by a pressure applied by the rest members.